2.
1) x+8/x-2=0
x+8/4x-2=0, x≠1/2
x+8=0
x=-8, x≠1/2
x=-8.
2) x²-25/x-5=0
x²-25=0
x²=25
x=±5
x=-5, x≠5
x=5
x=-5.
3) x(2-x)/81+x²=0
x+(2-x)/81+x²=0, xr
81+x²
x×(2-x) =0
x=0
2-x=0
x=0
x=2
x1=0, x2=2.
4)(2x-1)(x+3)/2x+1=0
(2x-1)×(x+3)/2x+1=0, x≠-1/2
(2x-1)×(x+3)=0
2x-1=0
x+3=0
x=1/2, x≠-1/2